This invention relates to a power supply apparatus for supplying power generated by a fuel cell to an electronic device, possibly for charging a battery of said electronic device. We also disclose a controller for controlling the flow of power between the power supply apparatus and the electronic device.
Fuel cells may be used to provide electrical power for electronic devices, such as mobile telephones, portable music players, tablet computers or laptop computers. Typically these electronic devices receive their power from the mains electricity supply. However, when mains electrical power is not available, for example, a fuel cell based power supply apparatus may be used. Such a fuel cell power supply apparatus may comprise a fuel cell that receives a fuel from a fuel storage vessel and any other reactants and generates electrical power which it can then supply to an electronic device coupled to it. The fuel cell power supply apparatus may be portable and include a replaceable fuel storage vessel and is therefore particularly convenient for providing power to use or charge an electronic device.
Conventional electrochemical fuel cells convert fuel and oxidant, generally both in the form of gaseous streams, into electrical energy and a reaction product. A common type of electrochemical fuel cell for reacting hydrogen and oxygen comprises a polymeric ion (proton) transfer membrane, with fuel and air being passed over respective sides of the membrane. Protons (that is, hydrogen ions) are conducted through the membrane, balanced by electrons conducted through a circuit connecting the anode and cathode of the fuel cell. To increase the available voltage, a stack may be formed comprising a number of such membranes arranged with separate anode and cathode fluid delivery channels. Such a stack is typically in the form of a block comprising numerous individual fuel cell plates held together by end plates at either end of the stack. The anode delivery channels are formed in flow plates that extend between an anode inlet manifold and an anode outlet manifold. The cathode delivery channels are also formed in flow plates between a cathode inlet manifold and a cathode outlet manifold. The fuel cell plates may have the anode delivery channels on one side and the cathode delivery channels on the other side. Electrical energy generated by the stack may be received from stack terminals and can then be supplied to other devices.